IPA: /ˈɡraɪndɪŋli/
KK: /ˈɡraɪndɪŋli/
In a manner that involves grinding or is very slow and difficult.
The machine worked grindingly, taking hours to complete the task.
Grindingly → It is formed from "grind" (from Old English "grindan", meaning to crush or grind) and "-ly" (a suffix meaning in a manner of). The word "grindingly" means in a manner that involves crushing or grinding.
Think of the action of 'grinding' — it means to crush something down, and the '-ly' shows how it's done. So, grindingly means doing something in a crushing manner.